1. Field of the Invention
The present invention relates to an image forming apparatus such as a copier with an electronic sorting function and an image forming method, and to an information processing method and system.
2. Related Background Art
A digital copier with an electronic sorting function is known in which all images are read and stored once in a memory such as a hard disk and thereafter image data of desired originals is read and printed out. Copies of desired originals can therefore be obtained without using a sorter unit having a plurality of bins.
An electronic sorting function which can use PDL (page description language) data is also known in which a digital copier receives, from a network, PDL data formed by an application at a host computer, develops it into bit map images and stores them once in a memory such as a hard disk, and thereafter desired images are read from the memory to print them out in a sorted state.
PDL data formed by an application is sent from a host computer to a digital copier, generally in the order from the start page to the last page. Therefore, in order to print out copies in a face-up state and in a binding order, it is necessary to print out each page in a reverse order. Therefore, developed images are required to be stored once in a memory such as a hard disk and thereafter images are read from the memory in the order from the last page to the first page to print them out in a binding order.
Any hard disk has a capacity limit so that this capacity may become full while images are sequentially read from the start page. For example, assuming that PDL data has a total amount of 120 pages and the capacity of a hard disk becomes full when first to 100th pages are stored, it is not possible to continuously output 120 pages in a face-up state and in the reverse order. When the capacity of the hard disk becomes full, the following operations may be performed. One is to automatically cancel the print job. Another is to first print out first to 100th pages in a face-up state for the requested number of sheets per page, and then to store 101st to 120th pages in the hard disk and read these pages in a reverse order from the hard disk to print them out in a face-up state for the requested number of sheets per page.
However, with the above operations, all necessary pages cannot be sequentially printed out after the capacity of a memory such as a hard disk becomes full.